The number of people killed in China by the new coronavirus has risen to 81, with almost 3,000 confirmed ill. The national new year holiday has been extended by three days to Sunday, in an attempt to contain the spread. On Monday, Chinese Premier Li Keqiang visited Wuhan, the capital of Hubei province and centre of the outbreak. The number of deaths in Hubei rose from 56 to 76, with five deaths elsewhere. Wuhan is in lockdown and several other cities have imposed travel bans. In Shanghai, the government has stopped businesses from returning to work until 10 February. The ban applies to all companies apart from utilities, medical firms, medical suppliers, and supermarkets. Meanwhile, the director-general of the World Health Organization, Tedros Adhanom Ghebreyesus, is in Beijing to discuss the outbreak with the Chinese government and health experts. Experts suspect many more people are infected, but actual figures are hard to ascertain due to a number of factors like some people being asymptomatic. Prof Neil Ferguson, a public health expert at Imperial College, London, told the UK's Guardian newspaper his "best guess" put the number at 100,000 infected, while figures put together by the Li Ka Shing Faculty of Medicine of the University of Hong Kong suggest the number was closer to 43,000. However, the University of Hong Kong research also suggested that - without public health intervention - tens of thousands more could be infected every day when the outbreak reaches its height. As a result of their projections, Gabriel Leung, the dean of the faculty of Medicine, was advising "substantial, draconian measures" to limit population mobility. The coronavirus causes severe acute respiratory infection and there is no specific cure or vaccine. Most of the deaths have been of elderly people or those with pre-existing respiratory problems.